Due to the increasing number of technical components being used in motor vehicles, it is necessary to optimize the installed size of these components in order to ensure the desired functionality that is achieved by incorporating the components. For instance, large-volume air conditioning components, such as are known in the form of mixing chambers, flow deflector devices and swirling devices in stationary air conditioning systems, cannot be used in motor vehicles due to the limited space conditions.
As an added requirement, automotive air conditioning systems, which are used to condition an infed flow of air, divide said flow if necessary, and channel the individual air flows into different regions of the vehicle, must supply air flows at different temperatures to different air vents in the air conditioning system, depending on the position and function of these vents. In this process, the infed flow of air is guided across various heat exchangers so that the air can be cooled and dehumidified and, if necessary, reheated before being channeled into the passenger compartment. For example, the air is blown into the footwell and via openings in the dashboard into the passenger compartment, and is also guided through vents directly to the windshield for defogging or defrosting the windshield. In generic air conditioning systems which are controlled in terms of air flow, the air flow to be supplied to the passenger compartment is divided into two partial air flows by means of a damper, also called a temperature control damper. The desired temperatures of the air flows are adjusted by means of the temperature control damper and various control mechanisms. In this process, one partial air flow is channeled through a heating heat exchanger located in the lower portion of the system and is heated. At the same time, the second partial air flow bypasses the heating heat exchanger as cold air. The two partial air flows at different temperatures are then combined in order to achieve the desired set temperature.
In conventional air conditioning systems, the partial air flows are not optimally mixed. When the temperature control damper is in an intermediate position, air at different temperatures is delivered to the various air vents in the passenger compartment. The varying temperatures in the air flows at the different vents, for example the footwell vents, dashboard vents and window vents, is referred to as air stratification.
To decrease stratification between certain vents, warm air ducts are provided specifically for deflecting warm air to the vent at the windshield, for example; as added elements, these ducts adversely affect the air flow rate and acoustics, and at the same time result in higher costs.
Other known air conditioning systems have a temperature control damper combined with an enlarged mixing zone, which are designed to channel the cold air flow in the direction of the warm air flow, and to guide the air flows through the enlarged mixing zone to ensure adequate mixing. Thorough mixing is achieved in this case due to the size of the mixing zone. Alternatively or additionally, some air conditioning systems are designed with baffle plates or deflection plates, particularly in the mixing zone area, as restricting elements or throttling elements that are designed to generate turbulence within the air flow to be mixed. The added plates which decrease the flow cross-section for the air flow increase the flow rate. At the same time, pressure losses also increase.
It is likewise known in the prior art to design air conditioning systems such that the warm air flow and the cold air flow are channeled to meet one another head-on and are then mixed with one another to ensure better blending.
Other embodiments of conventional systems comprise deflection plates which dam the various air flows at certain locations within the system as needed, block passage, and prevent the air from flowing through.
The baffle plates, deflection plates, restricting elements, and throttling elements may be formed on the temperature control damper itself, for example.
Also known in the prior art are systems having more than two flow paths for the air, in which the air has different temperatures within the flow paths.
EP 1 336 517 A1 discloses an air conditioning system having an evaporator arranged in an air duct, and a heating heat exchanger arranged downstream in the direction of air flow. The air flow conditioned in the evaporator can then be divided into three different flow paths, with one flow path acting as the warm air duct and deflecting the air through the heating heat exchanger and the other two flow paths acting as cold air ducts or as bypasses and each deflecting the air past the heating heat exchanger. The various flow paths serve to avoid heavy stratification, resulting in an improved temperature distribution in the air flow.
However, said air conditioning system, which comprises sliding dampers and/or rotatable dampers along with the associated drive technology, requires a structurally highly complex control of the air flow through and/or around the heating heat exchanger. Moreover, the air conditioning system is designed with a plurality of mixing chambers and requires substantial installation space.
Alternative designs for air conditioning systems having a plurality of sliding dampers and/or rotating dampers and the drive technology associated with each of these are known in the prior art.
For instance, DE 196 03 126 A1 discloses an automotive air conditioning system designed for selectively opening at least three vents. The air conditioning system comprises a housing, a rotary shaft mounted rotatably in the housing, and an arcuate rotary door, which is connected to the rotary shaft. The rotary door has a plurality of openings and a drive means for rotating the rotary shaft. The housing is designed with a plurality of ducts that lead to the vents, the intake openings of which are arranged along the circumferential surface of the rotary door. The intake openings of the ducts are closed and/or opened by means of the rotary door, allowing the flow of air coming from a mixing chamber and having a uniform temperature to be divided among a plurality of ducts.
A common feature of the systems known in the prior art is that they involve additional, highly costly elements which require additional space and added expense, along with additional assembly expenditure and corresponding maintenance costs. The additional fixtures also create boundaries and narrowed areas in the flow passages, resulting in increased air flow pressure losses, which in turn leads to increased power requirements and thus increased energy consumption, and to a decrease in the efficiency of the air conditioning system and thus of the entire vehicle.
In addition to significant flow losses, the damper geometries known from the prior art also produce loud flow noises. Pivoting the dampers can generate vibrations.
The object of the present invention is to provide an air conditioning system which offers both optimal blending with minimal stratification in terms of air flow temperatures, and minimal expenditure on temperature control, in accordance with requirements. In particular, the system should ensure that the flow of air in one of the main flow directions, in which no or only slight blending of the air flows is required, is not influenced or is minimally influenced, while at the same time a duct for a second flow of air is at least partially closed. In this system, the air should be selectively channeled, and both the number of components used and the amount of installation space required should be minimal. The costs of producing, assembling and maintaining said system should be minimal.